Case presentation

A 28-year-old man presented to the ED with chest, abdominal, and back pain. His history
was significant for sickle cell disease with recurrent crises, and the majority of
his pain was consistent with previous pain crises. On further questioning, he noted
pleuritic chest pain localized to his right chest and dyspnea on exertion for two
days. He reported no recent travel, leg swelling, or personal history of malignancy
but he had had a subsegmental pulmonary embolism three years prior that was treated
with four months of dabigatran. Surgical history included multiple surgical repairs
of a fractured right femur. He had no family history of coagulopathy. Outpatient medications
included cholecalciferol 2000 IU/d; folic acid 1 mg/d; oxycodone extended release
40 mg every 12 hours; and oxycodone 30 mg every 4 hours.

The patient was in no acute distress and was afebrile, with a blood pressure of 139/62
mm Hg, a heart rate of 90 beats/min, a respiratory rate of 20 breaths/min, and an
oxygen saturation of 91% on room air. The physical exam was remarkable for clear lungs
without wheezing or rhonchi, lower extremities without edema, and reproducible bony
tenderness over the thorax in various areas including the right and left lateral chest
walls. The remainder of the examination was normal. An electrocardiogram (EKG) demonstrated
sinus bradycardia, left ventricular hypertrophy, and no ST-T wave abnormalities. Admission
labs revealed a hemoglobin level of 9.3 g/dL, a white blood cell count of 8.14 cells/mm3, a platelet count of 502,000 cells/mm3, a creatinine level of 0.6 mg/dL, a troponin level below 0.03 ng/mL, and a reticulocyte
count of 11.60%. The rest of his labs were normal.

A chest X-ray with two views showed no active disease. Given the patient's history
of pulmonary embolism, pleuritic chest pain, and hypoxia, CT angiography of the chest
was obtained, which revealed a right-lower-lobe subsegmental pulmonary embolism.

CHEST 2016 guidelines recommend ruling out proximal DVT when SSPE is detected. If
lower-extremity ultrasound reveals no proximal DVT and the patient is considered to
be at low risk for recurrence, then simply monitoring with lower-extremity ultrasound
is recommended (11. Kearon C, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report. Chest.
2016;149:315-52. [PMID: 26867832]). Patients may be considered to have low risk for recurrence if they are not hospitalized,
have normal mobility, do not have cancer, and have no history of recent surgery.

Sickle cell disease creates a pro-thrombotic state with risk of in-situ thrombosis.
This may be a separate entity from VTE. Nonetheless, rates of VTE in patients with
sickle cell disease mirror those of patients with inherited thrombophilia (1919. Shet AS, Wun T. How I diagnose and treat venous thromboembolism in sickle cell disease. Blood. 2018;132:1761-9. [PMID: 29764840].-2121. Naik RP, Streiff MB, Haywood C Jr, Nelson JA, Lanzkron S. Venous thromboembolism in adults with sickle cell disease: a serious and under-recognized
complication. Am J Med. 2013;126:443-9. [PMID: 23582935]) which would suggest also a higher risk of VTE recurrence. It has been extrapolated
that a provoked VTE in a patient with sickle cell disease carries a much higher risk
of recurrence compared to the general population and therefore indefinite anticoagulation
should be recommended (1919. Shet AS, Wun T. How I diagnose and treat venous thromboembolism in sickle cell disease. Blood. 2018;132:1761-9. [PMID: 29764840].).

Conclusion

This case highlights several challenges in the management of SSPE. No prospective
data exist to guide the management of SSPE. Patients with underlying pro-thrombotic
disorders—especially those with malignancy or sickle cell disease—could
very well be at risk for clot propagation. According to current guidelines, when SSPE
is detected, clinicians should rule out concomitant lower-extremity DVT. If it is
ruled out and the patient is at low risk for recurrence, it is reasonable for anticoagulation
to be held and the patient to be monitored with lower-extremity ultrasound (11. Kearon C, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report. Chest.
2016;149:315-52. [PMID: 26867832]). No clear recommendations exist on how to treat patients with high risk of bleeding.
For patients at risk for recurrence or with diminished cardiopulmonary reserve, anticoagulation
is recommended. Patients with cancer or sickle cell disease likely represent a population
at greater risk for recurrence and therefore should receive anticoagulation. The duration
of anticoagulation for SSPE in these populations is unclear.

Back to the case

After our patient was diagnosed with SSPE, a lower-extremity ultrasound was done and
no DVT was seen. In light of his previous pulmonary embolism and presumed increased
risk of recurrence due to sickle cell disease, we decided to treat him with anticoagulation
indefinitely. His symptoms were probably due to symptomatic SSPE. His pain improved
and he was discharged on rivaroxaban.

Dr. Gary is a third-year resident in internal medicine and Dr. Sobuto is a fellow
in pulmonology and critical care at Lankenau Medical Center in Wynnewood, Pa. Dr.
Cohen is an internist at Lankenau Medical Center with a special interest in vascular
disorders and is a clinical professor of medicine at the Sidney Kimmel Medical College
of Thomas Jefferson University in Philadelphia. Disclosures: Dr. Cohen reports a speakership
with Janssen.

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